Aquatic exercise such as aqua aerobics may be performed for improving or maintaining fitness or for rehabilitation, for example from injury. Land based exercise can involve high stresses on muscles and joints due to gravity, for example when running or jumping. Exercising in water can avoid such stresses due to the buoyancy force provided by the water counteracting a person's body weight. Thus, aqua exercise may be particularly attractive to the elderly or overweight people, or to people recovering from injury or requiring physical rehabilitation, as the water supports the person during exercise.
Such benefits of exercising in water are advantageous to people of all ages and levels of fitness, including healthy and athletic people. Exercising in water may also be particularly useful to those who have a high level of fitness including elite athletes, as water provides resistance against movement that is proportional to the effort exerted in movement. Moving quickly in water increases the amount of resistance acting on a person's body many times more than resistance due to air when performing the same motion on land.
The use of aqua resistance equipment may be used to increase the resistance that water provides against a user's movement in water to improve strength and aerobic fitness and other related benefits, while avoiding land based disadvantages caused by gravity acting on the body when performing exercises.
Example leg fin devices are described in WO2016/083984 and U.S. Pat. No. 7,621,851. Aqua exercise resistance equipment may be difficult to use. For example, aqua exercise resistance equipment may not provide a correct or desired level of resistance against movement in water. Also, equipment can be difficult for a user to attach, or to adjust for use by different people, or to adjust to create different levels of resistance for one person to satisfy a personal training regime. Components of equipment can deteriorate when used in chlorinated water and an entire equipment assembly may need to be replaced. Furthermore, aqua exercise resistance equipment may provide an unbalanced or different level of resistance in opposite directions of movement which can be undesirable.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.